ramshackles
Well-known member
I've been working on trying to make a simple opamp power supply that has high efficiency - high enough to go without a heatsink.
I am basing it around the TPS7A* regulators from TI and the Bourns CD-HD2004 schottky diode bridge.
The maximum dropout of this pair should be ~1.3V at the max load of 1A (typical is ~0.815V). Reducing the load to 500mA should reduce the dropout to ~0.78V
So on to the transformer selection. Ideally, I dont want to have all these efficient parts only to have to deal with a load of excess from the transformer.
12VAC is a common tx value and would give me an RMS of 17V. I think this may be cutting it too fine for a +/- 16V output.
So, I thought; how about a transformer rated at 12V AC for a larger-than-needed current? (e.g. 12VAC @ 2A), this would, in theory, give me a slightly higher VAC at lower current draw. Is it unreasonable to rely on 'side-effects'?
schematic:
https://ramshackleaudio.s3.amazonaws.com/media/images/ps_1.original.png
https://ramshackleaudio.s3.amazonaws.com/media/images/ramshackle_power_supply_1.original.png
I am basing it around the TPS7A* regulators from TI and the Bourns CD-HD2004 schottky diode bridge.
The maximum dropout of this pair should be ~1.3V at the max load of 1A (typical is ~0.815V). Reducing the load to 500mA should reduce the dropout to ~0.78V
So on to the transformer selection. Ideally, I dont want to have all these efficient parts only to have to deal with a load of excess from the transformer.
12VAC is a common tx value and would give me an RMS of 17V. I think this may be cutting it too fine for a +/- 16V output.
So, I thought; how about a transformer rated at 12V AC for a larger-than-needed current? (e.g. 12VAC @ 2A), this would, in theory, give me a slightly higher VAC at lower current draw. Is it unreasonable to rely on 'side-effects'?
schematic:
https://ramshackleaudio.s3.amazonaws.com/media/images/ps_1.original.png
https://ramshackleaudio.s3.amazonaws.com/media/images/ramshackle_power_supply_1.original.png